The first 911 call arrived at 9:35 am in the emergency communications center at the Newtown Police Department on Main Street.

Gunman at Sandy Hook Elementary School. Shots fired.

The two dispatchers on duty initiated the department's active-shooter policy. Every officer, off duty and on patrol, was notified via radio. The station emptied out.

It's a 2.3-mile drive from the Newtown station to Sandy Hook Elementary School: A left, a right and another right. The first on the scene were nine Newtown officers, divided into three teams of three, including the police chief. They were the first, after the shooter, to force their way into the school, via the front lobby and the rear door.

Inside: silence. The air smelled like the department's firing range: spent gunpowder.

By that time, 1,000 feet down the road from the school, William Halstead, the chief of Sandy Hook Volunteer Fire and Rescue, knew something was wrong. From his desk, he had heard the sirens as the first squad cars passed — a typical sound for this stretch of Route 6, which connects Newtown's Main Street with Interstate 84 — but he thought nothing of it until the noise began to compound.

More sirens, as Connecticut State Police and other Newtown officers zoomed by.

More sirens, as ambulances arrived from the Newtown Volunteer Ambulance Corps and Danbury Hospital.

And then the fire chief and four others — including his daughter, the station's captain of emergency medical services, and a firefighter whose son attended Sandy Hook — hopped in a rescue truck for the short ride up the hill. A small army of volunteer first responders — two dozen EMTs from Newtown's ambulance corps alone — flocked to the scene. Everyone's pagers and radios had alerted them to the situation, and neighbors raced to help neighbors.

Dozens of units from several jurisdictions would follow, barreling up Dickinson Drive toward the school, where the initial report indicated an active threat and multiple casualties. But the reality that greeted most first responders was confounding: There were people to evacuate but none to save.

Triage tarps were laid out in the parking lot anyway.

Stretchers and backboards were unloaded and lined up for nobody.

EMTs and firefighters stood like sentinels outside the school, waiting to be useful, even after a paramedic exited the building and told Chief Halstead that everybody who was still inside would not be coming out.

Newtown, for a first responder, is a motor vehicle accident on one of the area's 270 miles of roads. Newtown is a heart attack at one of its senior-citizen communities. It's an episode of domestic abuse or petty larceny. It's brush fires and downed wires and abdominal pain. Occasionally, it's a car wreck that requires extrications or a house fire with a couple of victims. It is not a rifle-powered massacre.

"You know, it was horrific . . ."

This is Newtown's chief of police, Michael Kehoe, two weeks after the shooting at Sandy Hook.

". . . absolutely horrific . . ."

He's been a police officer in town for 341/2 years, chief since 2001. He was one of the first nine officers into the school on Dec. 14.

". . . to believe that somebody would do that . . ."

Kehoe sat at his desk Friday, calm and cordial and somber, a green-and-white ribbon pinned by a tiny gold angel to his crisp white dress shirt. His team was trained and ready for an active-shooter scenario, but there hadn't been one in Newtown in decades — perhaps not since 1975, when the proprietor of the Sandy Hook Hotel shot and killed two Hell's Angels in an act that was deemed self-defense. Before Dec. 14, the last local crime to draw continuous national news coverage was an airline pilot's murder of his wife; he disposed of her body via a wood chipper near Lake Zoar in 1986, and the trial lasted for weeks.

Those incidents pale in comparison to what happened two weeks ago, Kehoe said. Since then, his department has been consumed by the two ghastly crime scenes, the first being that of the shooter's mother, by attempts at defrauding or violating the privacy of the victims' families, by a battery of media requests and intrusions that have encouraged a no-comment policy for now. Connecticut State Police officials aren't talking about the event, and last week, a judge in Danbury Superior Court extended the seal on five related search warrants for another 90 days as the investigation continues.

Kehoe will speak only broadly about Dec. 14 and its effects on his team.

"I think there's a general concern about law enforcement officers, EMS, firefighters," Kehoe said. "We all see horrific things in our daily jobs. . . . Certainly, at all times we are really concerned about first responders who saw unimaginable things that day. . . . We tell officers, 'Feel free to see the clinician of your choice and get the help you need for you and your families.' "

The town's gratitude is visible. Outside the station, a big sign fixed to a tree on a neighboring property says, "THANK YOU FIRST RESPONDERS." Less than a mile up Main Street, entire walls of the Newtown Volunteer Ambulance Corps' station are papered with thank-you cards and e-mail printouts from far-flung people expressing their awe, thanks and best wishes ("I would like to wish you a safe journey"). From this station, 70 unpaid EMTs take turns serving 60 square miles and responding to 150 to 200 calls a month.

On Thursday afternoon at 3:30, EMT Mike Collins returned to the steepled station, located on a former gas-station plot, after attending a single-vehicle accident on the highway (driver dozed off, injuries were minor). With 21/2 hours left in his 12-hour shift, Collins considered the conundrum of arriving at a scene that can't be triaged. On Dec. 14, the ambulance corps was adrenalized and ready to serve. Collins was halfway to Sandy Hook in his own vehicle when word came over the radio that the ambulances were being sent back to the station.

He sat in the station for the next 10 hours as his fellow EMTs returned, visibly shaken from responding to a tragedy of such magnitude and irreversibility.

"In my mind, it's a nonvisual, it's an imaginary scene," said Collins, 61, who joined the corps in 2005, when he moved from California to Newtown for the peace and quiet. "Other people saw the real scene. . . . It was a heavy load on all those guys. I saw one of the police officers that Sunday night, and this guy was a tough cookie, and you could see his eyes were all red from crying."

The area's previous mass-casualty event, as recalled by Robert Grossman, was the 1965 crash landing of a passenger jet outside Danbury following a mid-air collision. Grossman, who is president of the volunteer ambulance corps' administrative body and a former trauma surgeon, was at that scene and remembers the severity of the passengers' burns. There were more than 50 people to evacuate and save from that scene. On Dec. 14, none of Newtown's EMTs entered the school.

"There's the feeling of inadequacy, that they were unable to do anything," Grossman said. "And many of them for the next number of days were unable to sleep. And had trouble eating. Typical post-traumatic stress disorder."

The day after the shooting, there was a meeting for all first responders at the volunteer fire hall near the school. Federal emergency-response officials laid out what Newtown's police officers and personnel would be feeling and when, told them it was normal and advised them on how to address their grief and trauma. Volunteer firefighters had their own meeting the following Tuesday.

"It's a debriefing from a messed-up scene, from a bad call," said Halstead, a 48-year veteran of firefighting who, since 1978, has been chief of the volunteer company, speaking Friday at his desk at the station. "The idea is, get people's feelings out there. . . . I don't care who you are, how big of a department you are. You're not ready for that amount of death."

A single call can transform a first responder's life, says William Keegan, a retired lieutenant with the Port Authority Police Department who was a night operations commander for the World Trade Center rescue-and-recovery teams after the Sept. 11, 2001, terrorist attacks.

A routine morning. A 2.3-mile drive to an incident. A still-life tableau of murdered first-graders.

"That was the first thing I thought of: these poor cops that walked into the classroom" and saw "bloody little kids, bodies blown apart," said Keegan, founder of H.E.A.R.T. 9/11, a group that helps communities cope with disasters and related trauma. "Nobody knows what that looks like until you see it. . . . It's all just horrifying. It's stuff they'll never forget."

Counselors have been continuously available to first responders in Newtown. Kehoe has urged his officers to stay home if they need to. Collins said volunteer EMTs are watching each other for signs of trauma-related stress. Halstead is planning another meeting for his firefighters shortly after the new year begins. And first responders are continuing to do their jobs, which for now include looking after the victims' families.

At the Dec. 19 funeral of 7-year-old Daniel Barden, a phalanx of firefighters (some from out of state) lined the entrance to the church, and hundreds were present for the burial. Since the massacre, two state troopers have kept watch over the Barden family, turning first response into a continuous response, said Daniel's father, Mark.

"As I write this," e-mailed Mark Barden on Friday evening, "Trooper Tamia Tucker and my niece Lauren are sitting on the floor playing dolls with my 11-year-old daughter Natalie. Trooper Dennis Keane is sitting at the kitchen table with my wife Jackie and her siblings, having a nice visit. They have transcended their role as state-appointed assistance and will forever be family to us."

Kehoe tempers the trauma of Dec. 14 with the notion that his team of nine stopped the massacre from continuing, but he hesitates to call himself a first responder.

"The first responders were the teachers and the students," he said at his desk, in front of a framed painting of the town flagpole frozen at half-staff. "Their actions clearly saved lives. . . . From [the shooter] being confronted by staff, from teachers closing doors, from teachers hiding students and going into training they're drilled on — all those were precious moments that took up extra time and allowed us to get there. They weren't equipped to deal with this at all. They're the true heroes."